Question 1

You are a researcher specializing in cytology,specifically the cell structures of the skeletal muscle that moves the body.The instrument that you would use to see the fine detail within cells would be the
A) MRI scan.
B) light microscope.
C) scanning electron microscope.
D) transmission electron microscope.
E) CT scan.

Accepted Answer

The transmission electron microscope (TEM) is best suited for viewing the fine details within cells, particularly the internal structures of organelles such as the skeletal muscle in question. MRI and CT scans use different imaging techniques and are not suitable for examining the internal structures of cells. While the scanning electron microscope (SEM) can provide a high-resolution image of the surface structures of cells, it is not ideal for imaging the internal structures. The light microscope is limited in its ability to resolve the fine details within cells due to diffraction of light.

Question 2

Which of the following is a function of the membrane proteins called channel proteins?
A) They bind to specific extracellular molecules to trigger a cellular change.
B) They permit the passage of ions, bypassing the lipid portion of the cell membrane.
C) They are enzymes.
D) They serve as anchors or stabilizers for the cell membrane.
E) They are used as a source of energy.

Accepted Answer

Channel proteins are membrane proteins that form a channel or pore through the lipid bilayer, allowing ions and other small molecules to pass through, bypassing the hydrophobic lipid portion of the membrane. This function is important for maintaining proper concentrations of ions and nutrients inside the cell, as well as facilitating communication and signaling between cells.

Question 3

Membrane-bound proteins that allow identification of a cell as "self" or "nonself" are called ________ proteins.
A) integral
B) recognition
C) carrier
D) peripheral
E) channel

Accepted Answer

The function described in the question is that of recognition proteins, which are responsible for identifying cells as "self" or "nonself". Integral, carrier, and channel proteins could be involved in transport or other functions, but they do not play the specific role of cell recognition. Peripheral proteins are typically found on the surface of the cell membrane, but again, their function is not specifically related to cell recognition.

Question 4

The concept that each cell of an organism maintains homeostasis is part of our understanding of
A) cell theory.
B) Darwinian theory.
C) the cell cycle.
D) mitotic theory.
E) the theory of differentiation.

Accepted Answer

The concept of each cell maintaining homeostasis is part of cell theory, which states that all living things are made up of cells, cells are the basic unit of life, and all cells come from pre-existing cells.

Question 5

The smallest living things are
A) proteins.
B) organ systems.
C) tissues.
D) organs.
E) cells.

Accepted Answer

Cells are the smallest living unit of organisms. They are able to carry out all functions necessary for life, including obtaining energy, responding to stimuli, and reproducing. Proteins are molecules made up of amino acids and are not considered living things. Organ systems, tissues, and organs are composed of multiple cells and are larger than a single cell.

Question 6

Immersion of red blood cells into a(n)________ solution results in lysis of the cell.
A) isotonic
B) hypertonic
C) hypotonic
D) monotonic
E) equilibrated

Accepted Answer

When red blood cells are immersed in a hypotonic solution, water enters the cells due to osmosis, leading to swelling and eventual lysis (bursting) of the cells.

Question 7

Crenation occurs when a blood cell is placed in a(n)
A) isotonic solution.
B) pinocytotic solution.
C) hypotonic solution.
D) monotonic solution.
E) hypertonic solution.

Accepted Answer

Crenation occurs when a blood cell is placed in a hypertonic solution, meaning the solution has a higher concentration of solutes than the inside of the blood cell. This causes water to move out of the cell, leading to a shriveling or "crenated" appearance.

Question 8

Which of the following terms is used to define the structure that separates the contents of a human cell from its surrounding medium?
A) cell wall
B) cell layer
C) plasma membrane
D) cell boundary
E) nuclear envelope

Accepted Answer

The plasma membrane is a thin layer that separates the contents of a human cell from its surrounding medium. The cell wall is only present in plant cells, and the nuclear envelope is a structure that surrounds the nucleus within the cell. The terms "cell layer" and "cell boundary" are not commonly used to describe the structure that separates a cell's contents from its surrounding medium.

Question 9

Looking at a tissue through a microscope,you notice that all of the cells along the free surface of the tissue have microvilli along the free edges of the cells.This would tell you that this tissue has what function?
A) the need to detoxify many chemicals
B) a high metabolic rate
C) phagocytosis
D) motility
E) absorption

Accepted Answer

The presence of microvilli indicates an increase in surface area, which is typically associated with absorption. Therefore, the best choice is E (absorption).

Question 10

Structurally,the plasma membrane
A) contains no imbedded proteins.
B) separates the chromatin from the cytoplasm in eukaryotes.
C) contains carbohydrate molecules only.
D) is nonporous.
E) is composed of a bilayer of lipids.

Accepted Answer

The plasma membrane is composed of a bilayer of lipids, specifically phospholipids, which forms a flexible barrier that separates the cell from its environment. It also contains embedded proteins that perform various functions such as transportation of molecules and cell signaling. Carbohydrate molecules are present on the surface of the membrane, but not the entire membrane itself. The membrane is also selectively permeable, allowing certain molecules to pass through while excluding others.

Question 11

The phosphate "head" of a phospholipid is
A) hydrophobic.
B) hydrophilic.
C) polar.
D) nonpolar.
E) both hydrophilic and polar.

Accepted Answer

The phosphate "head" of a phospholipid is both hydrophilic, meaning it is attracted to water, and polar, which refers to a distribution of electric charge leading to parts of the molecule having partial positive and negative charges. These properties allow the phospholipid to interact with water and form the bilayer structure of cell membranes, with the hydrophilic heads facing the aqueous environments inside and outside the cell, and the hydrophobic tails facing each other.

Question 12

Opening a bottle of perfume releases perfume molecules from the container,and within a few minutes the perfume can be smelled by a person many feet away from the bottle.This illustrates
A) diffusion.
B) facilitated diffusion.
C) osmosis.
D) filtration.
E) active transport.

Accepted Answer

The movement of perfume molecules from the container to someone's nose many feet away is an example of diffusion, which is the movement of particles from an area of high concentration to an area of low concentration.

Question 13

Which of the following is a concept of the cell theory?
A) Cells are the basic structural unit of life.
B) Tissues are the site of control.
C) Organelles are the basic functional unit of life.
D) Cells are produced by meiosis.
E) Cells are immortal.

Accepted Answer

The concept of the cell theory is that cells are the basic structural unit of life. This includes all organisms – from simple unicellular organisms to complex multicellular organisms.

Question 14

Flu viruses enter into a prospective host cell (along the respiratory tract)and direct it to produce many copies of the viruses.As those viruses bud off of the infected cell,they take the cell membrane of the host cell with them.How might this kill the host cell?
A) The infected host cell loses the ability to transport materials in and out.
B) The infected cell cannot metabolize.
C) The infected cell cannot make RNA.
D) The infected cell loses the ability to move towards nutrient sources.
E) None of these is correct.

Accepted Answer

The bud off of viruses from the infected cell takes cell membrane with them, which can result in the loss of the host cell's ability to transport materials in and out. This can lead to the death of the cell.

Question 15

Plasma membranes allow certain molecules to pass,while blocking others.Membranes with this property are called
A) impermeable.
B) freely permeable.
C) selectively permeable.
D) actively permeable.
E) nonpermeable.

Accepted Answer

Plasma membranes are selectively permeable, which means they allow certain molecules to pass through while blocking others. This is necessary for cells to maintain their internal environment and regulate the exchange of nutrients, waste products, and other molecules with their surroundings. Impermeable membranes would not allow any molecules to pass through, while freely permeable membranes would allow all molecules to pass through indiscriminately. Actively permeable membranes require energy to transport molecules, and nonpermeable membranes do not exist in living cells.

Question 16

The movement of water across a membrane from an area of higher water (lower solute)concentration to an area of lower water (higher solute)concentration is known as
A) filtration.
B) active transport.
C) diffusion.
D) facilitated diffusion.
E) osmosis.

Accepted Answer

The movement of water across a membrane from an area of higher water (lower solute) concentration to an area of lower water (higher solute) concentration is known as osmosis. Choice A (filtration) involves the movement of small solutes across a membrane under pressure, choice B (active transport) involves the movement of solutes against their concentration gradient with the use of energy, choice C (diffusion) involves the movement of solutes from an area of high concentration to an area of low concentration, and choice D (facilitated diffusion) involves the movement of solutes across a membrane with the help of transport proteins.

Question 17

The plasma membrane
A) is a watery gel in which structures are suspended.
B) contains the powerhouse of the cell.
C) is the central government of the cell.
D) regulates the exchange of substances with the environment.
E) carries the cell's hereditary information.

Accepted Answer

The plasma membrane, also known as the cell membrane, is a selectively permeable barrier that regulates the exchange of substances with the environment. It is made up of a phospholipid bilayer embedded with proteins and other molecules that help facilitate transport and communication.

Question 18

Which substances can pass directly through the plasma membrane?
A) carbohydrate-bound
B) water soluble
C) lipid insoluble
D) iron soluble
E) lipid soluble

Accepted Answer

Only lipid-soluble substances can pass directly through the plasma membrane as it is primarily composed of phospholipids that form a hydrophobic barrier.

Question 19

Which of these transport mechanisms do not fit into the rest of the group listed?
A) osmosis
B) diffusion
C) ion pumps
D) passive transport
E) facilitated diffusion

Accepted Answer

Osmosis, diffusion, passive transport, and facilitated diffusion are all examples of substances moving across a membrane without the input of energy from the cell. Ion pumps, however, require the input of energy (usually ATP) to move substances against their concentration gradient. Therefore, ion pumps do not fit into the group of transport mechanisms that operate without the input of energy.

Question 20

The membrane proteins that are sensitive to extracellular materials are called
A) receptor proteins.
B) channel proteins.
C) carrier proteins.
D) anchor proteins.
E) identifier proteins.

Accepted Answer

Receptor proteins are membrane proteins that are sensitive to extracellular materials and bind to specific molecules outside of the cell, triggering a response within the cell. Channel and carrier proteins are types of membrane proteins that are involved in transport, but they do not necessarily interact with extracellular materials in a specific way. Anchor and identifier proteins are also types of membrane proteins, but they do not have a specific sensitivity to extracellular materials.

Quiz 3: Cell Structure and Function

You are a researcher specializing in cytology,specifically the cell structures of the skeletal muscle that moves the body.The instrument that you would use to see the fine detail within cells would be the

Which of the following is a function of the membrane proteins called channel proteins?

Membrane-bound proteins that allow identification of a cell as "self" or "nonself" are called ________ proteins.

The concept that each cell of an organism maintains homeostasis is part of our understanding of

The smallest living things are

Immersion of red blood cells into a(n) ________ solution results in lysis of the cell.

Crenation occurs when a blood cell is placed in a(n)

Which of the following terms is used to define the structure that separates the contents of a human cell from its surrounding medium?

Looking at a tissue through a microscope,you notice that all of the cells along the free surface of the tissue have microvilli along the free edges of the cells.This would tell you that this tissue has what function?

Structurally,the plasma membrane

The phosphate "head" of a phospholipid is

Opening a bottle of perfume releases perfume molecules from the container,and within a few minutes the perfume can be smelled by a person many feet away from the bottle.This illustrates

Which of the following is a concept of the cell theory?

Flu viruses enter into a prospective host cell (along the respiratory tract) and direct it to produce many copies of the viruses.As those viruses bud off of the infected cell,they take the cell membrane of the host cell with them.How might this kill the host cell?

Plasma membranes allow certain molecules to pass,while blocking others.Membranes with this property are called

The movement of water across a membrane from an area of higher water (lower solute) concentration to an area of lower water (higher solute) concentration is known as

The plasma membrane

Which substances can pass directly through the plasma membrane?

Which of these transport mechanisms do not fit into the rest of the group listed?

The membrane proteins that are sensitive to extracellular materials are called